#pragma once

namespace huobi_futures
{
	namespace utils
	{
		static const std::string base64_chars =
			"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
			"abcdefghijklmnopqrstuvwxyz"
			"0123456789+/";

		static inline bool is_base64(unsigned char c)
		{
			return (isalnum(c) || (c == '+') || (c == '/'));
		}

		std::string base64_encode(unsigned char const *bytes_to_encode, unsigned int in_len)
		{
			std::string ret;
			int i = 0;
			int j = 0;
			unsigned char char_array_3[3];
			unsigned char char_array_4[4];

			while (in_len--)
			{
				char_array_3[i++] = *(bytes_to_encode++);
				if (i == 3)
				{
					char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
					char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
					char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
					char_array_4[3] = char_array_3[2] & 0x3f;

					for (i = 0; (i < 4); i++)
						ret += base64_chars[char_array_4[i]];
					i = 0;
				}
			}

			if (i)
			{
				for (j = i; j < 3; j++)
					char_array_3[j] = '\0';

				char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
				char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
				char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
				char_array_4[3] = char_array_3[2] & 0x3f;

				for (j = 0; (j < i + 1); j++)
					ret += base64_chars[char_array_4[j]];

				while ((i++ < 3))
					ret += '=';
			}

			return ret;
		}

		std::string base64_decode(const std::string &encoded_string)
		{
			int in_len = encoded_string.size();
			int i = 0;
			int j = 0;
			int in_ = 0;
			unsigned char char_array_4[4], char_array_3[3];
			std::string ret;

			while (in_len-- && (encoded_string[in_] != '=') && is_base64(encoded_string[in_]))
			{
				char_array_4[i++] = encoded_string[in_];
				in_++;
				if (i == 4)
				{
					for (i = 0; i < 4; i++)
						char_array_4[i] = base64_chars.find(char_array_4[i]);

					char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
					char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
					char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];

					for (i = 0; (i < 3); i++)
						ret += char_array_3[i];
					i = 0;
				}
			}

			if (i)
			{
				for (j = i; j < 4; j++)
					char_array_4[j] = 0;

				for (j = 0; j < 4; j++)
					char_array_4[j] = base64_chars.find(char_array_4[j]);

				char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
				char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
				char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];

				for (j = 0; (j < i - 1); j++)
					ret += char_array_3[j];
			}

			return ret;
		}
	} // namespace utils
} // namespace huobi_futures